1. Field of the Invention
The present invention relates to a direct drive bearing mechanism capable of appropriately supporting a linearly displaceable (operable) member.
2. Description of the Related Art
A guide mechanism, which smoothly supports a slider for reciprocating in the axial direction of an actuator body, has been provided for a linear actuator and so on.
As shown in FIG. 15, the guide mechanism includes a pair of opposing first ball-rolling grooves 2a, 2b which extend axially on inner wall surfaces of a recess of a frame 1 and each of which has a vertical cross section of a circular arc shape, a pair of second ball-rolling grooves 4a, 4b which are formed on side surfaces of the slider 3 opposed to the inner wall surfaces of the frame 1 and each of which has a vertical cross section of a circular arc shape, and a pair of ball-circulating rolling holes 5a, 5b which are disposed near the second ball-rolling grooves 4a, 4b and which penetrate through the slider 3 in the axial direction of the slider 3.
The guide mechanism further includes plates 7 and covers 8 which are integrally connected to lower portions of end surfaces of the slider 3 by screw members 6, and return guides 10 which are installed to the end surfaces of the slider 3 to change the rolling direction of balls 9. Ball return grooves 11 are formed on the covers 8. Endless circulating tracks, in which the plurality of balls 9 roll and circulate, are constructed by the mutually opposing first and second ball-rolling grooves 2a, 2b, 4a, 4b, the penetrating ball-circulating rolling holes 5a, 5b formed through the slider 3, and the ball return grooves 11.
In the conventional guide mechanism, the plurality of balls 9 roll and circulate along the endless circulating tracks. Consequently, the slider 3 is smoothly guided in the axial direction of the frame 1.
However, in the conventional guide mechanism, the number of parts is increased because it is necessary to prepare the plurality of members such as the return guides 10 and the covers 8. Further, it is necessary to perform the boring machining for forming the ball-circulating rolling holes 5a, 5b for circulating the plurality of returned balls 9. Therefore, in the technical field to which the guide mechanism is applied, it has been demanded that the number of parts is reduced to simplify the assembling operation, and the machining steps are curtailed as far as possible to decrease the production cost.
A general object of the present invention is to provide a direct drive bearing mechanism which reduces the number of parts and simplifies the assembling operation by adopting a non-circulating system for balls.
A principal object of the present invention is to provide a direct drive bearing mechanism which curtails the machining steps and further reduces the production cost.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.